An ideal coating composition for filling small gaps in a semiconductor device must meet the following requirements: (1) Holes whose aspect ratio (i.e. height/diameter ratio) is 1 or more and diameter is 70 nm or less in a substrate must be able to be completely filled by a general spin-coating technique and the substrate must be able to be planarized to have a uniform thickness; (2) No air voids and cracks must be present in the coating film; (3) The thickness of the film must be uniform regardless of the density of the holes in the substrate; (4) The planarized film must be able to be removed at a desired rate by the treatment with a hydrofluoric acid solution after thermal curing without leaving any residue inside the holes; and (5) The coating composition must be stable during storage.
Carbon-based polymers have been used to fill small gaps in semiconductor devices. Recent miniaturization of semiconductor devices has led to a reduction in the size of holes to below 70 nm. However, when conventional carbon-based polymers are finally removed by ashing, the inner surfaces of holes are toughened, which causes difficulty in applying dielectric materials in the subsequent processing step. Thus, there is a need for novel compositions for filling small gaps in semiconductor devices that eliminate the need for ashing to reduce the cost of processing equipment and can be effectively removed by wet etching using a hydrofluoric acid solution for the removal of oxides present in patterned holes.